The idea of traffic signals timed to improve traffic flow isn’t new — 50 years ago, drivers going through West Philadelphia to Center City could hit nothing but green lights for about 30 blocks by maintaining a designated speed — but those older systems were static. Current systems that collect data from strategically-placed sensors and process it quickly can determine on the fly which lights should be red and which should be green.

And they could be improving. Surtrac, using technology patented by the Robotics Institute at Carnegie Mellon University, claims its technology can produce 25 percent reductions in travel time and 40 percent reductions in time spent waiting at intersections.
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